Hemiancistrus cerrado, de Souza & Melo & Chamon & Armbruster, 2008

de Souza, Lesley S., Melo, Marcelo R. S., Chamon, Carine C. & Armbruster, Jonathan W., 2008, A new species of Hemiancistrus from the rio Araguaia basin, Goiás state, Brazil (Siluriformes: Loricariidae), Neotropical Ichthyology 6 (3), pp. 419-419 : 419-

Hemiancistrus cerrado , new species

Figs. 1-2

Holotype. MZUSP 89074, 125.3 mm SL, Brazil, Goiás, município Goiás Velho, rio Bugre, tributary of rio Vermelho , underneath bridge on road GO-164, 25 km NW of Goiás, 15°47’13”S, 50°07’53”W, 24 Jul 2005, M. R. S. Melo, L. S. de Souza, C. C. Chamon & L. M. de Sousa.

Paratypes. Brazil, Goiás, rio Araguaia drainage: AUM 45427, 4 , 68.1-123.6 mm SL and MZUSP 98668 , 6 (1 cs), 50.8-136.9 mm SL, same data as holotype. MZUSP 26549 , 1, 170.4 mm SL, rio Vermelho at the mouth of rio Bugre , 15°49’S, 50°19’W, 7 Dec 1981, J. C. Garavello, A. Copriva, L. L. Ferreira. MZUSP 89389 , 1, 112.2 mm SL, between município Crixás / Santa Terezinha de Goiás, rio Crixás-Açu , underneath bridge on road GO-465, 14°26’26”S, 49°42’07”W, 28 Jul 2005, M. R. S. Melo, L. S. de Souza, C. C. Chamon & L. M. de Sousa .

Non-type specimens (juvenile, tentative identification). MZUSP 89048 , 1 , 24.3 mm SL, município Faina, rio do Peixe 2, tributary of rio do Peixe at road GO- 164 km 84, 15º20’51”S, 50º24’30”W, 4 Jul 2005, C. C. Chamon, M . R. S. Melo, L. M. de Sousa & L. S. de Souza .

Diagnosis. Hemiancistrus cerrado can be distinguished from H. chlorosticus , H. fuliginosus , H. guahiborum , H. meizospilos , H. subviridis , and H. votouro by having dark spots (vs. light spots); from H. landoni and H. medians by lacking spots on the abdomen (vs. spots present in adults); from H. micromattos , H. sabaji , H. snethlageae , H. spilomma , H. spinosissimus by having an emarginate caudal fin (vs. forked); from H. snethlageae by lacking faint zig-zag lines along the sides outlining dorsolateral plates (vs. faint zig-zag lines present); from H. landoni by lacking papillae on exposed surfaces (vs. papillae present, especially well developed on skin around orbit and eye); and from H. sabaji by having the spots on the sides all about the same size (vs. getting larger posteriorly) and the spots separate on the caudal fin (vs. combining to form bands on the lower lobe in adults).

Hemiancistrus cerrado is very similar to H. megalopteryx and H. punctulatus but can be distinguished by having a larger internares W/HL (15.9-21.1% vs. 11.2-14.0% in H. megalopteryx and 11.2-13.9% in H. punctulatus ), can usually be distinguished by having a larger adipose-fin spine L/SL ratio (9.4-13.6% vs. 7.1-8.7% in H. megalopteryx and 7.4- 10.0% in H. punctulatus ); and from H. megalopteryx by having the pelvic-fin spine reaching maximally to the middle of the pelvic fin spine when adpressed in adult males (vs. reaching the tip).

Description. Morphometrics in Table 1. Largest specimen examined 170.3 mm SL. Counts and measurements based on 13 specimens. Head and nape forming arc from tip of snout to insertion of dorsal fin. Dorsal slope decreasing in straight line to insertion of dorsal procurrent caudal rays then ascending to caudal fin. Ventral profile flat to caudal fin. Caudal peduncle triangular in cross section with dorsal surface flattened. Body widest at insertion of pectoral fins, narrowest insertion of caudal fin. Snout rounded.

Eyes moderately sized, dorsal rim of orbit forming tall crest that continues forward to area just anterior of nares as low, rounded ridge. Interorbital space largely flat, but with slight, rounded, median hump contiguous with rounded ridge on snout formed from mesethmoid. Slight ridge formed between anterodorsal margin of orbit and nares. Supraoccipital pointed posteriorly with posterior point raised above nuchal region in small crest. Infraorbitals, frontal, nasal, pterotic, and supraoccipital supporting odontodes. Preopercle and opercle not supporting odontodes. Opercle sickle shaped.

Lips covered with short, wide papillae. Size of papillae decreasing towards posterior margin of lower lip, bucal central papillae present and well developed. Lower lip wide, upper lip narrow. Edge of lower lip with small crenulae. Maxillary barbel reaching about one-third of distance to gill opening.

Median plates 24-27 (mode 25). Plates unkeeled, but first four or five plates of mid-ventral series bent to form slight ridge. Five caudal peduncle plate rows. Plates on all dorsolateral surfaces of body except for extreme edge of snout that only has narrow column of platelets on either side of snout tip. Throat mostly covered in platelets except for area right below lower lip. Abdomen naked or sparsely covered in platelets over and slightly posterior to pectoral bridge, laterally between pectoral and pelvic fins, and small region around anus. Cheek plates supporting hypertrophied odontodes evertible perpendicular to head. Cheek odontodes nine to 29 (mode 15). Longest evertible cheek odontode reaching middle of lateral process of cleithrum. Hypertrophied cheek odontodes relatively weak. Slightly longer odontodes present along dorsal-, adipose-, pelvic-, caudal-, and pectoralfin spines; larger individuals with hypertrophied odontodes

L. S. de Souza, M. R. S. Melo, C. C. Chamon & J. W. Armbruster 421

at tip of pectoral spine.

Dorsal fin II,7; dorsal-fin spinelet V-shaped, dorsal-fin locking mechanism present, last ray of dorsal fin almost reaching adipose-fin base when adpressed. Adipose fin with single preadipose plate and moderately long spine. Caudal fin I,14,I; caudal fin slightly emarginate, ventral lobe longer than dorsal lobe; dorsal and ventral procurrent caudal rays four to five (mode four). Pectoral fin I,6; pectoral-fin spine

422 A new species of Hemiancistrus from the rio Araguaia basin reaching just posterior to insertion of pelvic fin when adpressed. Pelvic fin I,5; pelvic-fin spine extending to base of anal fin when adpressed. Anal fin I,4; anal-fin spine slightly shorter than first ray.

Teeth bicuspid with lateral lobe three-quarters length of medial lobe and distal tip of lateral cusp one-half width of tip of medial cusp. Left dentary teeth 58-95 (mode 72). Left premaxillary teeth 55-91 (mode 71).

Color. Base color brown or gray in preserved specimens. Head and nape almost completely dark brown with large dark spots sometimes becoming mottled distally. Pectoral fin brown with dark brown large oblong spots on fin membranes and rays. Pectoral, pelvic, dorsal, anal and caudal fins slightly lighter than body, with dark, large oblong spots on fin membranes and rays. Spots in caudal fin arranged in three to five regular (contiguous along height of fin) or irregular (ventral and dorsal parts offset) bands; lighter interspaces light gray, usually slightly narrower than spots. Largest individual examined with light interspaces much narrower than spots, spots very irregular. Body with four saddles slightly darker than intervening areas, first below anterior end of dorsal fin, second with anterior half below posterior end of dorsal fin and posterior half behind dorsal fin, third beginning one to two plates anterior of preadipose plate to about posterior third of adipose-fin membrane, and fourth beginning just posterior to adipose fin to end of caudal peduncle. Ventral surface uniformly light except for blotches from anterior insertion of anal fin to caudal fin. Color in life similar to preserved coloration except base light brown and spots on body more intense.

Distribution and habitat. Known from rio do Bugre, rio Vermelho and probably rio do Peixe, tributaries of rioAraguaia in Goiás State, Tocantins Basin ( Fig. 3 ). Collected in second order streams in swift rocky riffles ( Fig. 4 ).

Etymology. Named after the Brazilian Cerrado, where the species is found. A noun in apposition.

Comparative material. Hemiancistrus punctulatus: MZUSP 37857, 13, Brazil, Rio Grande do Sul State, Município Jaguarão, confluence of rio Telho into rio Jaguarão , laguna Mirim drainage, approx. 32º30’S 53º27’W, MCP 17622, 5 of 23, Rio Grande do Sul State, rio dos Sinos, 2 km from Caraá, at Passo da Forquilha , 29º46’S 50º23’W. Further material listed by Armbruster (2008).

Figures

Fig. 1. Hemiancistruscerrado in lateral, dorsal and ventral views:MZUSP 89074,holotype, 125.3 mm SL,Brazil,Goiás, município Goiás Velho, rio Bugre, tributary of rio Vermelho, underneath bridge on road GO-164, 25 km NW of Goiás. Photos by M. Melo.

Fig. 2. Live specimen of Hemiancistrus cerrado, MZUSP 98668, paratype, 136.8 mm SL. Photo by L. de Sousa.

Fig. 3. Geographical distribution of Hemiancistrus cerrado, open symbol represents the type locality.Abbreviations stand for Brazilian the states of Goiás (GO), Mato Grosso (MT), Tocantins (TO), and the Distrito Federal (DF).

Fig.4. Rio Bugre, GoiásVelho municipality, Goiás, Brazil, type locality of Hemiancistrus cerrado. Photo by L. de Sousa.